Conus achatinus Gmelin, 1791

Franklin, J. Benjamin, Subramanian, K. A., Fernando, S. Antony & Krishnan, K. S., 2009, 2250, Zootaxa 2250, pp. 1-63 : 12-17

1. Conus achatinus Gmelin, 1791 ( Figure 2)

Conus achatinus Gmelin, 1791: 3388 , no. 25 (representation of lectotype, Chemnitz 1788: pl. 142, fig. 1317 (74 x 42 mm) ( Kohn 1966); "Oceano americano", corrected to " Java " ( Coomans et al. 1979b)).

Conus achatinus Hwass in Bruguière, 1792: 671–673, no. 66 (lectotype, MHNG (68.5 x 40.5 mm) (Kohn 1968); "Océan asiatique").

Conus ranunculus Hwass in Bruguière, 1792: 671, no. 65 (holotype, MHNG (45 x 23 mm) (Kohn 1968); "Océan Amériquain").

Cucullus ventricosus Röding, 1798: 49 , no. 623/114.

Conus achatinus var. infumata Dautzenberg, 1937: 12 (representation of lectotype, Chemnitz 1788: pl. 142, fig. 1320 (60 x 31 mm) ( Walls 1979)).

Material examined: MBMCS 101 , 5 specimens, SL 35–65 mm; SW 17–32 mm .

Description. Shell moderately solid, outline convex. Aperture wider at base than near shoulder. Spire of moderate height. Colour of body whorl olive or orange red to blackish brown, clouded with scattered white to dull yellowish flammules and blotches; broad band at centre with similar pattern. Spiral uniform thin lines of dark brown interrupted by white dots and dashes run from shoulder to base. Aperture bluish white; exterior dark colour pattern visible as a band along interior border of lip. Periostracum brown and opaque. End of siphon dark brown, proboscis deep orange to red.

Distribution. Melvill & Abercrombie (1893) first reported C. achatinus from India as ‘ C. monachus Linnaeus var. achatinus Chemnitz’. C. achatinus was reported to be widely distributed along northwest coast from Okha southward to Goa ( Melvill & Abercrombie 1893; Abercrombie 1893; Melvill & Standen 1901; Hornell & Tomlin 1951; Subrahmanyam et al. 1952; Kohn 1978). Ray (1949) reported two specimens from the east coast.

The specimens reported herein were collected from Keelakarai ( Table 6) by trawling in 5–20 m and by diving in 10 m. Fifty-eight specimens from Colaba, Bombay were collected by hand at low tide .

Remarks. In Colaba, Bombay (18 0 53’N 72 0 48’E), C. achatinus (piscivore) occurs together with C. hyaena (vermivore) on the upper intertidal region of the west coast, but it occurs only subtidally on the east coast.

Four types of shell colour patterns were observed among C. achatinus found on the west coast (Figure 62A, B, C & D) whereas only one type was observed in the east ( Figure 2). The size range was similar between both coast specimens.